Various nickel and palladium complexes, for example of xcex1-diimines substituted at the carbon atoms by heteroatoms such as nitrogen or oxygen, and selected ureas and urethanes, may be used as polymerization catalysts for olefins such as ethylene. The palladium catalysts also polymerize polar comonomers.
Recently polymerization catalysts containing late transition metals such as palladium and nickel have been reported. Among these compounds are complexes of xcex1-diimines (see World Patent Application 96/23010) and various other types of ligands (see U.S. Pat. No. 5,714,556). These catalysts can, under various conditions, make unique polyolefins, such as those that contain xe2x80x9cabnormalxe2x80x9d branching patterns when compared to polymers made by the well known Ziegler-Natta- and metallocene-type catalysts. In addition some of these catalysts can polymerize olefins which are often not polymerizable with most catalysts based on transition metal compounds, for example polar olefins such as olefinic esters. Therefore, new olefin polymerization catalysts containing late transition metals are of great interest.
The use of palladium containing catalysts to polymerize olefins is described in S. Mecking, et al., J. Am. Chem. Soc., vol. 120, p. 888-899 (1998). Nickel diimine complexes as olefin polymerization catalysts are described in L. K. Johnson, et al., J. Am. Chem. Soc., vol. 117, p. 6414-6415 (1995), and L. K. Johnson, et al., J. Am. Chem. Soc., vol. 118, p.267-268 (1996). None of the catalysts described herein are described in these papers.
Certain iron, cobalt and molybdenum complexes of xcex1-diimines having nitrogen substituted in the backbone are described in M. Doring, et al., Z. Anorg. Allg. Chem., vol. 620, p. 551-560 (1994). None of these substituted xcex1-diimines or these metal complexes are claimed herein.
The reactions of various bis(imidoyl chlorides) of oxalic acid with amines, diamines and aminoalcohols to form various nitrogen and oxygen substituted xcex1-diimines is described in D. Lauder, et al., J. Prakt. Chem., vol. 337, p. 143-152 and ibid., p. 508-515 (1995). None of the substituted xcex1-diimines enumerated in these papers is claimed herein.
This invention concerns a first process for the polymerization of one or more olefins of the formula H2Cxe2x95x90CHR1 and optionally one or more olefins of the formula H2Cxe2x95x90CHR2, comprising, contacting said olefins with a complex containing a transition metal selected from the group consisting of palladium, nickel, titanium, zirconium, scandium, vanadium, chromium, iron, cobalt, and a rare earth metal and a ligand of the formula 
which is an active polymerization catalyst, wherein:
each R1 is independently hydrogen or alkyl;
each R2 is independently substituted alkyl or xe2x80x94CO2R50;
A and E are each independently oxygen, sulfur, phosphorous or nitrogen;
R3 and R8 are each independently hydrocarbyl or substituted hydrocarbyl provided that the carbon atom bound to the nitrogen atom is bound to at least two other carbon atoms;
R4, R5, R6 and R7 are each independently hydrocarbyl or substituted hydrocarbyl;
Ar1 and Ar2 are each independently aryl or substituted aryl;
R9 and R10 are each independently hydrocarbyl or substituted hydrocarbyl;
R50 is hydrocarbyl or substituted hydrocarbyl;
and provided that:
when said ligand is (II) or (III) said transition metal is nickel;
when H2Cxe2x95x90CHR2 is present a palladium complex is present;
the members of any one or more of the pairs R4 and R5, R6 and R7, R4 and R6, and R5 and R7 taken together may form a ring;
when A is oxygen or sulfur, R5 is not present; and
when E is oxygen or sulfur, R7 is not present.
This invention also concerns a second process for the polymerization of one or more olefins of the formula H2Cxe2x95x90CHR1 and optionally one or more olefins of the formula H2Cxe2x95x90CHR2, comprising, contacting said olefins, a first compound of the formula 
and:
(a) a second compound W, which is a neutral Lewis acid capable of abstracting Xxe2x88x92 from M to form WXxe2x88x92, and which is also capable of transferring an alkyl group or a hydride to M, provided that WXxe2x88x92 is a weakly coordinating anion; or
(b) a combination of a third compound which is capable of transferring an alkyl or hydride group to M and a fourth compound which is a neutral Lewis acid which is capable of abstracting Xxe2x88x92, a hydride or an alkyl group from M to form a weakly coordinating anion; or
(c) when at least one of X is a hydride or alkyl group, a fifth compound which is a cationic Lewis or Bronsted acid whose counterion is a weakly coordinating anion; wherein:
M is Ni, Pd, Ti, Zr, Sc, V, Cr, Fe, Co or a rare earth metal;
each X is independently a monoanion;
n is equal to the oxidation number of M;
each R1 is independently hydrogen or alkyl;
each R2 is independently substituted alkyl or xe2x80x94CO2R50;
A and E are each independently oxygen, sulfur, phosphorous, or nitrogen;
R3 and R8 are each independently hydrocarbyl or substituted hydrocarbyl provided that the carbon atom bound to the nitrogen atom is bound to at least two other carbon atoms;
R4, R5, R6 and R7 are each independently hydrocarbyl or substituted hydrocarbyl;
Ar1 and Ar2 are each independently aryl or substituted aryl;
R9 and R10 are each independently hydrocarbyl or substituted hydrocarbyl;
R50 is hydrocarbyl or substituted hydrocarbyl;
and provided that
when said first compound is (II) or (III), M is Ni;
the members of any one or more of the pairs R4 and R5, R6 and R7, R4 and R6, and R5 and R7 taken together may form a ring;
when H2Cxe2x95x90CHR2 is present a palladium complex is present;
when A is oxygen or sulfur, R5 is not present; and
when E is oxygen or sulfur, R7 is not present.
This invention also includes a compound of the formula 
wherein:
M is Ni, Pd, Ti, Zr, Sc, V, Cr, Fe, Co or a rare earth metal;
each X is independently a monoanion;
n is equal to the oxidation number of M;
A and E are each independently oxygen, sulfur, phosphorous, or nitrogen;
R3 and R8 are each independently hydrocarbyl or substituted hydrocarbyl provided that the carbon atom bound to the nitrogen atom is bound to at least two other carbon atoms;
R4, R5, R6 and R7 are each independently hydrocarbyl or substituted hydrocarbyl;
Ar1 and Ar2 are each independently aryl or substituted aryl;
R9 and R10 are each independently hydrocarbyl or substituted hydrocarbyl;
and provided that
when said compound is (V) or (VI), M is Ni;
the members of any one or more of the pairs R4 and R5, R6 and R7, R4 and R6, and R5 and R7 taken together may form a ring;
when A is oxygen or sulfur, R5 is not present; and
when E is oxygen or sulfur, R7 is not present.
Also disclosed herein is a compound of the formula 
wherein:
A and E are each independently oxygen, sulfur, phosphorous, or nitrogen;
R4, R5, R6 and R7 are each independently hydrocarbyl or substituted hydrocarbyl;
R11 is hydrocarbyl or substituted hydrocarbyl containing 2 or more carbon atoms, or a functional group;
R12, R13, R14, R15, R16, R17, R18, R19, and R20 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group;
and provided that
the members of any one or more of the pairs R4 and R5, R6 and R7, R4 and R6, and R5 and R7 taken together may form a ring;
any two of R11, R12, R13, R14, R15, R16, R17, R18, R19, and R20 vicinal to one another taken together may form a ring with the further proviso that if R11 and R12 are taken together to form a ring, then R11 and R12 taken together contain at least 2 carbon atoms;
when A is oxygen or sulfur, R5 is not present; and
when E is oxygen or sulfur, R7 is not present.
Herein, certain terms are used. Some of them are:
A xe2x80x9chydrocarbyl groupxe2x80x9d is a univalent group containing only carbon and hydrogen. If not otherwise stated, it is preferred that hydrocarbyl groups (and alkyl groups) herein contain 1 to about 30 carbon atoms.
By xe2x80x9csubstituted hydrocarbylxe2x80x9d herein is meant a hydrocarbyl group which contains one or more substituent groups which are inert under the process conditions to which the compound containing these groups is subjected. The substituent groups also do not substantially interfere with the process. If not otherwise stated, it is preferred that substituted hydrocarbyl groups herein contain 1 to about 30 carbon atoms. Included in the meaning of xe2x80x9csubstitutedxe2x80x9d are heteroaromatic rings.
By xe2x80x9c(inert) functional groupxe2x80x9d herein is meant a group other than hydrocarbyl or substituted hydrocarbyl which is inert under the process conditions to which the compound containing the group is subjected. The functional groups also do not substantially interfere with any process described herein that the compound in which they are present may take part. Examples of functional groups include halo (fluoro, chloro, bromo and iodo), trialkylsilyl, ether such as xe2x80x94OR22 wherein R22 is hydrocarbyl or substituted hydrocarbyl. In cases in which the functional group may be near a nickel or palladium atom the functional group should not coordinate to the metal atom more strongly than the groups in those compounds are shown as coordinating to the metal atom, that is they should not displace the desired coordinating group.
By an xe2x80x9calkyl aluminum compoundxe2x80x9d is meant a compound in which at least one alkyl group is bound to an aluminum atom. Other groups such as alkoxide, hydride, and halogen may also be bound to aluminum atoms in the compound.
By xe2x80x9cneutral Lewis basexe2x80x9d is meant a compound, which is not an ion, which can act as a Lewis base. Examples of such compounds include ethers, amines, sulfides, and organic nitrites.
By xe2x80x9ccationic Lewis acidxe2x80x9d is meant a cation which can act as a Lewis acid. Examples of such cations are sodium and silver cations.
By relatively noncoordinating (or weakly coordinating) anions are meant those anions as are generally referred to in the art in this manner, and the coordinating ability of such anions is known and has been discussed in the literature, see for instance W. Beck., et al., Chem. Rev., vol. 88 p. 1405-1421 (1988), and S. H. Strauss, Chem. Rev., vol. 93, p. 927-942 (1993), both of which are hereby included by reference. Among such anions are those formed from the aluminum compounds mentioned previously and Xxe2x88x92, including R333AlXxe2x88x92, R332AlClXxe2x88x92, R33AlCl2Xxe2x88x92, and xe2x80x9cR33AlOXxe2x88x92xe2x80x9d, wherein R33 is alkyl. Other useful noncoordinating anions include BAFxe2x88x92 {BAF=tetrakis[3,5-bis(trifluoromethyl)phenyl]borate}, SbF6xe2x88x92, PF6xe2x88x92, and BF4xe2x88x92, trifluoromethanesulfonate, p-toluenesulfonate, (RfSO2)2Nxe2x88x92, and (C6F5)4Bxe2x88x92.
By an empty coordination site is meant a potential coordination site that does not have a ligand bound to it. Thus if an ethylene molecule is in the proximity of the empty coordination site, the ethylene molecule may coordinate to the metal atom.
By a ligand that may add to an olefin is meant a ligand coordinated to a metal atom into which an olefin molecule as described above (or a coordinated olefin molecule) may insert to start or continue a polymerization. For instance, this may take the form of the reaction (wherein L is a ligand and the olefin is ethylene): 
By a rare earth metal is meant one of lanthanum, cerium, praeseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or lutetium.
Compounds of formulas (I) and (VII) can be made by the reaction of the corresponding bis(imidoyl chlorides) of oxalic acid with compounds containing primary or secondary amines, alcohols, phenols, thiols, phosphines, or a combination thereof, see for instance D. Lauder, et al., J. Prakt. Chem., vol. 337, p. 143-152 and ibid., p. 508-515 (1995), both of which are hereby included by reference, and the examples herein.
Compounds of formulas (II) and (III) may be made by the reaction of an organic isocyanate with the corresponding organic hydroxy compound, or primary or secondary amine, respectively.
The Ni and Pd and other metal complexes described herein may be made by various methods (depending on the other ligands present in the complex), and by methods described in World Patent Application 96/23010 and U.S. Pat. No. 5,714,556, both of which are hereby included by reference. The Examples herein also illustrate such methods. These complexes may be preformed, i.e., may be added to the polymerization process in a form in which the ligand (I), (II) or (III) is already complexed to the transition metal, or may be formed in situ, i.e., the transition metal (compound) and ligand are added separately to the polymerization process, but the desired complex forms in situ. This includes all instances when precursors to the desired transition metal complex are added. For instance the transition metal may be added in the form of an M[0] complex, such as bis(cyclooctadiene)nickel, in which the nickel may be oxidized to Ni[II] by reaction with HY, wherein Y is a relatively noncoordinating anion. Other methods of forming such complexes in situ are found in World Patent Application 96/23010 and U.S. Pat. No. 5,714,556.
In (I) and (VII), and in all other compounds in which these substituents occurs, it is preferred that:
A and E are each independently nitrogen or oxygen, more preferably both A and E are nitrogen; and/or
A and E are both oxygen; and/or
A is nitrogen or phosphorous, more preferably nitrogen, and R4 and R5 taken together for a ring; and/or
R4 and R6 taken together form a ring, more preferably xe2x80x94(CH2)zxe2x80x94 wherein z is 2 or 3; and/or
R3 is 
xe2x80x83wherein R23, R24, R25, R26 and R27 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, provided that any of R23, R24, R25, R26 and R27 vicinal to one another taken together may form a ring; and/or
R8 is 
xe2x80x83wherein R28, R29, R30, R31 and R32 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, provided that any of R28, R29, R30, R31 and R32 vicinal to one another taken together may form a ring. In another preferred compound (I) or (VII) A and E taken together are part of a ring, where applicable in combination with any of the above.
In (II) or other compounds herein in which these groups occur, it is preferred that:
Ar1 is 
xe2x80x83wherein R34, R35, R36, R37 and R38 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, provided that any of R34, R35, R36, R37 and R38 vicinal to one another taken together may form a ring, and more preferably one or both of R34 and R38 are alkyl containing 1 to 4 carbon atoms, and/or R35, R36 and R37 are hydrogen; and/or
R9 is alkyl, substituted alkyl, aryl or substituted aryl, especially alkyl or 
xe2x80x83wherein R39, R40, R41, R42 and R43 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, provided that any of R39, R40, R41, R42 and R43 vicinal to one another taken together may form a ring, and more preferably one or both of R39 and R43 are alkyl containing 1 to 4 carbon atoms, and/or R40, R41 and R42 are hydrogen.
In (III) or other compounds herein in which these groups occur, it is preferred that:
Ar2 is 
xe2x80x83wherein R44, R45, R46, R47 and R48 are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, provided that any of R44, R45, R46, R47 and R48 vicinal to one another taken together may form a ring, and more preferably one or both of R44 and R48 are alkyl containing 1 to 4 carbon atoms, and/or R45, R46 and R47 are hydrogen; and/or
R10 is alkyl or substituted alkyl, especially hydroxyl substituted alkyl.
It is preferred that X is halide, alkyl, carboxylate or acetylacetonate, more preferably chloride, bromide or iodide. When X is alkyl it is more preferred that M is Pd and only one of X is alkyl.
It is preferred that R1 is hydrogen or n-alkyl containing 1 to 18 carbon atoms, more preferably hydrogen or methyl, and especially preferably hydrogen, or any combination thereof. It is also preferred that R2 is xe2x80x94(CH2)qR48 wherein q is 0 or an integer of 1 to 18 and R48 is a functional group, more preferably q is 0 and/or R48 is CO2R49, wherein R49 is hydrocarbyl or substituted hydrocarbyl, more preferably hydrocarbyl, and especially preferably alkyl.
In all complexes one preferred metal is nickel. In other complexes preferred metals are Ti, Zr, Sc, V, Cr or a rare earth metal, especially with (I) when R4 and R5 taken together form a ring, and R6 and R7 taken together do not form a ring.
In the first polymerization process described herein a nickel, palladium or other metal complex is either added to the polymerization process or formed in situ in the process. In fact, more than one such complex may be formed during the course of the process, for instance formation of an initial complex and then reaction of that complex to form a living ended polymer containing such a complex.
Examples of such complexes which may be formed initially in situ include 
wherein R3 through R8 and M are as defined above, T1 is hydride or alkyl or any other anionic ligand into which ethylene can insert, Y is a neutral ligand capable of being displaced by ethylene or a vacant coordination site, the xe2x80x9cparallel linesxe2x80x9d are an ethylene molecule coordinated to the metal, and Q is a relatively non-coordinating anion. Complexes may be added directly to the process or formed in situ. For instance, (XIII) may be formed by the reaction of (IV) with a neutral Lewis acid such as an alkyl aluminum compound. Another method of forming a complex in situ is adding a suitable nickel or palladium compound such as nickel [II] acetylacetonate, (I) and an alkyl aluminum compound. Other metal salts in which anions similar to acetylacetonate are present, and which may be removed by reaction with the Lewis or Bronsted acid, may also be used. For instance metal halides and carboxylates (such as acetates) may be used, particularly if they are slightly soluble in the process medium. It is preferred that these precursor metal salts be at least somewhat soluble in the process medium.
After the polymerization has started, the complex may be in a form such as 
wherein R3 through R8, M, and Q are as defined above, P is a divalent polymeric group such as a (poly)ethylene group of the formula xe2x80x94(CH2CH2)xxe2x80x94 wherein x is an integer of 1 or more, and T2 is an end group, for example the groups listed for T1 above. Those skilled in the art will note that (XV) is in essence a polymer containing a so-called living end. It is preferred that M be in +2 oxidation state in these compounds. Compounds such as (XIII), (XIV) and (XV) may or may not be stable away from an environment similar to that of the polymerization process, but they may be detected by NMR spectroscopy, particularly one or both of 1H and 13C NMR, and particularly at lower temperatures. Such techniques, especially for polymerization xe2x80x9cintermediatesxe2x80x9d of these types are known, see for instance World Patent Application 96/23010, especially Examples 197-203.
(XIII), (XIV) and (XV) may also be used, in the absence of any xe2x80x9cco-catalystsxe2x80x9d or xe2x80x9cactivatorsxe2x80x9d to polymerize one or more suitable olefins in a third polymerization process. Except for the ingredients in the process, the process conditions for the third process, such as temperature pressure, polymerization medium, etc., may be the same as for the first and second polymerization processes, and preferred conditions for those processes are also preferred for the third polymerization process.
In the first, second and third polymerization processes herein, the temperature at which the polymerization is carried out is about xe2x88x92100xc2x0 C. to about +200xc2x0 C., preferably about xe2x88x9260xc2x0 C. to about 150xc2x0 C., more preferably about xe2x88x9220xc2x0 C. to about 100xc2x0 C. The pressure of the olefin (if it is a gas) at which the polymerization is carried out is not critical, atmospheric pressure to about 275 MPa being a suitable range.
The polymerization processes herein may be run in the presence of various liquids, particularly aprotic organic liquids. The catalyst system, olefin, and polyolefin may be soluble or insoluble in these liquids, but obviously these liquids should not prevent the polymerization from occurring. Suitable liquids include alkanes, cycloalkanes, selected halogenated hydrocarbons, and aromatic hydrocarbons. Specific useful solvents include hexane, toluene, benzene, methylene chloride, and 1,2,4-trichlorobenzene.
The olefin polymerizations herein may also initially be carried out in the solid state by, for instance, supporting the nickel or palladium compound on a substrate such as silica or alumina, activating it with the Lewis (such as W, for instance an alkylaluminum compound) or Bronsted acid and exposing it to olefin. Alternatively, the support may first be contacted (reacted) with W such as an alkylaluminum compound, and then contacted with an appropriate transition metal compound such as (IV), (V) or (VI). The support may also be able to take the place of the Lewis or Bronsted acid, for instance an acidic clay such as montmorillonite. Another method of making a supported catalyst is to start a polymerization or at least make a transition metal complex of another olefin or oligomer of an olefin such as cyclopentene on a support such as silica or alumina. These xe2x80x9cheterogeneousxe2x80x9d catalysts may be used to catalyze polymerization in the gas phase or the liquid phase. By gas phase is meant that a gaseous olefin is transported to contact with the catalyst particle.
In all of the polymerization processes described herein oligomers and polymers of the various olefins are made. They may range in molecular weight from oligomeric olefins, to lower molecular weight oils and waxes, to higher molecular weight polyolefins. One preferred product is a polymer with a degree of polymerization (DP) of about 10 or more, preferably about 40 or more. By xe2x80x9cDPxe2x80x9d is meant the average number of repeat (monomer) units in a polymer molecule.
Depending on their properties, the polymer made by the processes described herein are useful in many ways. For instance if they are thermoplastics, they may be used as molding resins, for extrusion, films, etc. if they are elastomeric, they may be used as elastomers. If they contain functionalized monomers such as acrylate esters, they are useful for other purposes, see for instance World Patent Application 96/23010.
Polyolefins are most often prepared by polymerization processes in which a transition metal containing catalyst system is used. Depending on the process conditions used and the catalyst system chosen, polymers, even those made from the same monomer(s) may have varying properties. Some of the properties which may change are molecular weight and molecular weight distribution, crystallinity, melting point, and glass transition temperature. Except for molecular weight and molecular weight distribution, branching can affect all the other properties mentioned.
It is known that certain transition metal containing polymerization catalysts including those disclosed herein, are especially useful in varying the branching in polyolefins made with them, see for instance World Patent Applications 96/23010 and 97/02298, and U.S. patent application Ser. No. 09/006,628, filed Jan. 13, 1998, and Ser. No. 09/006,536, filed Jan. 13, 1998. It is also known that blends of distinct polymers, that vary for instance in the properties listed above, may have advantageous properties compared to xe2x80x9csinglexe2x80x9d polymers. For instance it is known that polymers with broad or bimodal molecular weight distributions may be melt processed (be shaped) more easily than narrower molecular weight distribution polymers. Similarly, thermoplastics such as crystalline polymers may often be toughened by blending with elastomeric polymers.
Therefore, methods of producing polymers which inherently produce polymer blends are useful especially if a later separate (and expensive) polymer mixing step can be avoided. However in such polymerizations one should be aware that two different catalysts may interfere with one another, or interact in such a way as to give a single polymer.
In such a process the catalysts disclosed herein can be termed the first active polymerization catalyst. Monomers useful with these catalysts are those described (and also preferred) above.
A second active polymerization catalyst (and optionally one or more others) is used in conjunction with the first active polymerization catalyst. The second active polymerization catalyst may be another late transition metal catalyst, for example as described in World Patent Applications 96/23010 and 97/02298, and U.S. patent application Ser. No. 09/006,628, filed Jan. 13, 1998, Ser. No. 09/006,536, filed Jan. 13, 1998, and Ser. No. 08/991,372, filed Dec. 16, 1997. Other useful types of catalysts may also be used for the second active polymerization catalyst. For instance so-called Ziegler-Natta and/or metallocene-type catalysts may also be used. These types of catalysts are well known in the polyolefin field, see for instance Angew. Chem., Int. Ed. Engl., vol. 34, p. 1143-1170 (1995), European Patent Application 416,815 and U.S. Pat. No. 5,198,401 for information about metallocene-type catalysts, and J. Boor Jr., Ziegler-Natta Catalysts and Polymerizations, Academic Press, New York, 1979 for information about Ziegler-Natta-type catalysts, all of which are hereby included by reference. Many of the useful polymerization conditions for all of these types of catalysts and the first active polymerization catalysts coincide, so conditions for the polymerizations with first and second active polymerization catalysts are easily accessible. Oftentimes the xe2x80x9cco-catalystxe2x80x9d or xe2x80x9cactivatorxe2x80x9d is needed for metallocene or Ziegler-Natta-type polymerizations. In many instances the same compound, such as an alkylaluminum compound, may be used as an xe2x80x9cactivatorxe2x80x9d for some or all of these various polymerization catalysts.
In one preferred process described herein the first olefin(s) [the monomer(s) polymerized by the first active polymerization catalyst] and second olefin(s) [the monomer(s) polymerized by the second active polymerization catalyst] are identical, and preferred olefins in such a process are the same as described immediately above. The first and/or second olefins may also be a single olefin or a mixture of olefins to make a copolymer. Again it is preferred that they be identical particularly in a process in which polymerization by the first and second active polymerization catalysts make polymer simultaneously.
In some processes herein the first active polymerization catalyst may polymerize a monomer that may not be polymerized by said second active polymerization catalyst, and/or vice versa. In that instance two chemically distinct polymers may be produced. In another scenario two monomers would be present, with one polymerization catalyst producing a copolymer, and the other polymerization catalyst producing a homopolymer, or two copolymers may be produced which vary in the molar proportion or repeat units from the various monomers. Other analogous combinations will be evident to the artisan.
In another variation of this process one of the polymerization catalysts makes an oligomer of an olefin, preferably ethylene, which oligomer has the formula R70CHxe2x95x90CH2, wherein R70 is n-alkyl, preferably with an even number of carbon atoms. The other polymerization catalyst in the process them (co)polymerizes this olefin, either by itself or preferably with at least one other olefin, preferably ethylene, to form a branched polyolefin. Preparation of the oligomer (which is sometimes called an xcex1-olefin) by a second active polymerization-type of catalyst can be found in World Patent Application 96/23010, and U.S. patent application Ser. No. 09/005,965, filed Jan. 12, 1998.
Likewise, conditions for such polymerizations, using catalysts of the second active polymerization type, will also be found in the appropriate above mentioned references.
Two chemically different active polymerization catalysts are used in this polymerization process. The first active polymerization catalyst is described in detail above. The second active polymerization catalyst may also meet the limitations of the first active polymerization catalyst, but must be chemically distinct. For instance, it may have a different transition metal present, and/or utilize a different type of ligand and/or the same type of ligand which differs in structure between the first and second active polymerization catalysts. In one preferred process, the ligand type and the metal are the same, but the ligands differ in their substituents.
Included within the definition of two active polymerization catalysts are systems in which a single polymerization catalyst is added together with another ligand, preferably the same type of ligand, which can displace the original ligand coordinated to the metal of the original active polymerization catalyst, to produce in situ two different polymerization catalysts.
The molar ratio of the first active polymerization catalyst to the second active polymerization catalyst used will depend on the ratio of polymer from each catalyst desired, and the relative rate of polymerization of each catalyst under the process conditions. For instance, if one wanted to prepare a xe2x80x9ctoughenedxe2x80x9d thermoplastic polyethylene that contained 80% crystalline polyethylene and 20% rubbery polyethylene, and the rates of polymerization of the two catalysts were equal, then one would use a 4:1 molar ratio of the catalyst that gave crystalline polyethylene to the catalyst that gave rubbery polyethylene. More than two active polymerization catalysts may also be used if the desired product is to contain more than two different types of polymer.
The polymers made by the first active polymerization catalyst and the second active polymerization catalyst may be made in sequence, i.e., a polymerization with one (either first or second) of the catalysts followed by a polymerization with the other catalyst, as by using two polymerization vessels in series. However it is preferred to carry out the polymerization using the first and second active polymerization catalysts in the same vessel(s), i.e., simultaneously. This is possible because in most instances the first and second active polymerization catalysts are compatible with each other, and they produce their distinctive polymers in the other catalyst""s presence. Any of the processes applicable to the individual catalysts may be used in this polymerization process with 2 or more catalysts, i.e., gas phase, liquid phase, continuous, etc.
The polymers produced by this process may vary in molecular weight and/or molecular weight distribution and/or melting point and/or level of crystallinity, and/or glass transition temperature and/or other factors. For copolymers the polymers may differ in ratios of comonomers if the different polymerization catalysts polymerize the monomers present at different relative rates. The polymers produced are useful as molding and extrusion resins and in films as for packaging. They may have advantages such as improved melt processing, toughness and improved low temperature properties.
Hydrogen may be used to lower the molecular weight of polyolefin produced in the first or second processes. It is preferred that the amount of hydrogen present be about 0.01 to about 50 mole percent of the olefin present, preferably about 1 to about 20 mole percent. When liquid monomers (olefins) are present, one may need to experiment briefly to find the relative amounts of liquid monomers and hydrogen (as a gas). If both the hydrogen and monomer(s) are gaseous, their relative concentrations may be regulated by their partial pressures.
In the Examples, certain abbreviations are used:
xcex94Hfxe2x80x94heat of fusion
BAFxe2x80x94tetrakis[bis(3,5-trifluoromethyl)phenyl]borate
DMAPxe2x80x944-dimethylaminopyridine
DSCxe2x80x94Differential Scanning Calorimetry (at a heating rate of 15xc2x0 C./min; first heat xe2x88x92150xc2x0 C. to +160xc2x0 C., second heat xe2x88x92150xc2x0 C. to +250xc2x0 C.)
EOCxe2x80x94end of chain
Etxe2x80x94ethyl
GPCxe2x80x94Gel Permeation Chromatography
MAO and PMAOxe2x80x94methylaluminoxane
Mexe2x80x94methyl
Mnxe2x80x94number average molecular weight
Mwxe2x80x94weight average molecular weight
PDIxe2x80x94polydispersity, Mw/Mn
RTxe2x80x94room temperature
TLCxe2x80x94Thin Layer Chromatography
Tgxe2x80x94glass transition temperature
Tm=melting point
TOxe2x80x94turnovers, moles of olefin polymerized per mole of transition metal compound
All pressures in the Examples are gauge pressures. Metal complexes are designated by the number of the ligand, the metal, and other ligands (neutral or charged) on the complex. For instance the complex of ligand 4 with NiBr2 is written as 4.NiBr2.
In the Examples, certain compounds are made and/or used. Their structures are shown below. 